Poly[co(4-oxybenzoate/phenyleneisophthalate)] is a previously known polymer which is disclosed in U.S. Pat. No. 3,637,595. However, such polymer is recognized to be difficult to form on a uniform and reliable basis. Such difficulty can be traced to its inherent structural morphology wherein the polymer when melted forms a biphasic melt. Some regions within the melt form an ordered anisotropic melt phase at a given temperature range and other regions form a nonordered isotropic melt phase. The nonuniformity of the product of the prior art also commonly has led to formation of three-dimensional molded articles having widely varying properties. See, (1) "Anomalous Temperature Dependence of Viscosity of Thermotropic Polyesters", by Gabor Kiss appearing in the Journal of Rheology 30(3), Pages 585 to 599 (1986), and (2) "Pressure-Induced Phases in a Thermotropic Polyester" by B.S. Hsiao, M. T. Shaw and E. T. Samulski appearing in Macromolecules, 21, Pages 543 to 545 (1988).
Numerous blends of distinct polymeric materials have been disclosed in the past. However, it has been recognized that the characteristics of the resulting blends commonly cannot be predicted with certainty and require empirical testing since the interaction of the diverse polymer chains within the blend is complex. In U.S. Pat. No. 4,267,289 is disclosed a blend of two specific polymers which each form an anisotropic single phase melt. Representative disclosures of polymer blends of an anisotropic melt-forming polymer and an isotropic melt-forming polymer are present in U.S. Pat. Nos. 4,228,218; 4,276,397; 4,386,174; 4,408,022; 4,429,078; 4,433,083; 4,442,057; 4,451,611; 4,489,190; 4,567,227; 4,460,735; 4,460,736; 4,611,025; and in European Patent Application Nos. 0170067; 0249226; and 0278066. U.S. Pat. No. 4,414,365 discloses a bulk phenyleneisophthalate)] wherein the resulting product exhibits improved melt processability.
It is an object of the present invention to provide an improved process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] wherein the resulting product exhibits anisotropic melt properties over a broader temperature range.
It is an object of the present invention to provide an improved process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] wherein the product exhibits enhanced physical and mechanical properties.
It is another object of the present invention to provide a novel relatively inexpensive polymeric composition of matter which is capable of exhibiting an anisotropic melt phase and of reliably undergoing melt processing to form quality three-dimensional molded articles.
It is a further object of the present invention to provide a novel polymeric composition of matter which is capable of undergoing melt processing to form a three-dimensional article which exhibits a heat deflection temperature of at least 200.degree. C. and a Notched Izod impact strength of at least 1.0 ft.-1b./in.
These and other objects, as well as the scope, nature and utilization of the claimed invention will be apparent to those skilled in the art from the following detailed description and appended claims.